Embodiments of this disclosure relate generally to fire protection systems, and more particularly, to a ballistic power panel that reduces fire in and around the fuel cell after a ballistic penetration of the fuel cell.
Aircraft that may be subjected to enemy gun fire generally have a fire suppression system to suppress fires in the areas surrounding the fuel cells after impact of the fuel cell from a ballistic round. There are currently three different passive approaches to reduce fire in and around a fuel cell after a ballistic penetration from an armor piercing round. They are: ballistic foam, aluminum oxide powder filled bags on the outside of the fuel cell, and aluminum oxide honeycomb powder filled panels.
When using ballistic foam, the ballistic foam has to be cut to fit the specific height of each individual frame of the fuel cell. The ballistic foam is then bonded into place. This practice requires many hand fitted foam blocks to be cut and bonded onto the structure and themselves. An additional ply of epoxy glass fabric is cured onto the interface surface of the foam blocks and the fuel tank assembly after all of the foam blocks has been installed and bonded. The ballistic foam is heavy and the installation is a time consuming and costly process. Furthermore, once the foam blocks have been bonded to the structure, it is difficult to have easy access to the structure in the advent of damage or inspection. This method also requires a separate ballistic liner to be manufactured and installed prior to the installation of the fuel tank further increasing the time, cost, and complexity for this process.
The other two approaches to reduce fire around a fuel cell after a ballistic penetration use aluminum oxide powder. In one approach, aluminum oxide filled bags are placed on the outside of the fuel cell. The use of aluminum oxide powder filled bags is heavy. Furthermore, an adhesive needs to be applied over the entire surface of the bags which further increases the weight and time for installation. It is also difficult to install the bags since there is a potential for the bags to tear.
The third approach is the use of a honeycomb panel filled with ballistic powder. This approach requires the individual cells to be filled with the aluminum oxide. There is a difficulty in filling the honeycomb cells to the appropriate level when the panel is flat, but it is even more difficult to fill the honeycomb cells with aluminum oxide powder when the panels are curved. The honeycomb panels are difficult to manufacture since the honeycomb cells have a tendency to either crush or deform when curved panels are manufactured. Also, during the curing process, resin may flow into the honeycomb cells partially blocking the honeycomb cells. The honeycomb panels have a single ply of fabric having a thin adhesive layer covering the honeycomb core cells. The removal of the face sheet off of the core sometimes damages the panel thus making installation difficult.
Therefore, it would be desirable to provide an apparatus that overcomes the above problems. The apparatus would overcome the cost, weight, accessibility and other issues associated with other prior art passive approaches to reduce fire in and around a fuel cell after a ballistic penetration.